Gel Calibration — How It Works

What Is FBI BB Calibration?

The FBI ballistic gelatin calibration standard was developed to ensure consistent, repeatable terminal ballistics testing across labs, agencies, and product batches. It uses a standardized projectile — a 590-grain steel BB — fired at a specific velocity into the gel at a specific temperature.

For a gel block to be considered correctly calibrated to the 10% FBI standard, a 590-grain steel BB fired at 590 ± 15 fps must penetrate 3.35 ± 0.30 inches (85 ± 8mm) into the block.

How We Calibrate Each Batch

1. Formulation — Raw materials are combined by weight to achieve the target gel percentage (10% or 20%). The ratio of polymer to mineral oil is precisely controlled.
2. Pour & Set — The gel is poured into calibration molds and allowed to set at room temperature for a minimum of 72 hours before calibration testing.
3. Temperature Conditioning — Calibration testing is performed at 39.2°F (4°C), the temperature standard used in organic gelatin testing for consistency with historical data.
4. BB Test — A 590-grain steel BB is fired at 590 fps ± 15 fps into the gel surface. The penetration depth is measured in millimeters at the point of deepest penetration.
5. Pass / Fail — If penetration is within 85 ± 8mm, the batch passes. Batches outside tolerance are reworked or discarded. The calibration result is recorded on the batch card.

What Calibration Means for Your Results

When you test ammunition in calibrated gel, your results are directly comparable to:

• FBI ammunition evaluation data
• Published ballistic testing from labs using the same standard
• Results from other calibrated Clear Ballistics blocks — even from different batches
• Historical data from organic gelatin tests that used the same standard

This cross-comparability is the entire point of the calibration standard. Without it, every test result is an island — interesting, but not generalizable.

Reading Your Batch Card

Every Clear Ballistics gel order ships with a batch calibration card that includes:

• Batch number and production date
• Gel formulation (10% or 20%)
• BB test velocity (fps)
• BB penetration depth (mm)
• Pass/fail notation and technician signature

Keep this card with your testing records. For law enforcement and military use, this documentation satisfies chain-of-custody and methodology traceability requirements for evidentiary testing.